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Abstract: SA-PO067

Admission Hyperphosphatemia Increases Risk of AKI in Hospitalized Patients

Session Information

Category: Acute Kidney Injury

  • 003 AKI: Clinical and Translational


  • Cheungpasitporn, Wisit, Mayo Clinic , Rochester, Minnesota, United States
  • Thongprayoon, Charat, Bassett Medical Center, Cooperstown, New York, United States
  • Mao, Michael A., Mayo Clinic , Rochester, Minnesota, United States
  • Kittanamongkolchai, Wonngarm, Mayo Clinic , Rochester, Minnesota, United States
  • Sakhuja, Ankit, Mayo Clinic , Rochester, Minnesota, United States
  • Erickson, Stephen B., Mayo Clinic , Rochester, Minnesota, United States

The association between elevated admission serum phosphate and risk of in-hospital acute kidney injury (AKI) is limited. The aim of this study was to assess the risk of AKI in hospitalized patients stratified by various admission serum phosphate levels.


This is a single-center retrospective study conducted at a tertiary referral hospital. All hospitalized adult patients who had admission phosphate levels available between January and December 2013 were enrolled. Admission phosphate was categorized based on its distribution into six groups (<2.4, 2.4 to 2.9, 2.9 to 3.4, 3.4 to 3.9, 3.9 to 4.4, and ≥4.4 mg/dL). The primary outcome was in-hospital AKI occurring after hospital admission. Logistic regression analysis was performed to obtain the odds ratio of AKI for various admission phosphate strata using the phosphate 2.4 to 2.9 mg/dL level (lowest incidence of AKI) as the reference group.


After excluding patients with ESRD, without serum creatinine measurement, and those who presented with AKI at the time of admission, a total of 5,036 patients were studied. Phosphate levels of <2.4 mg/dL and ≥4.4 mg/dL were found in 458 (9.1%) and 585 (11.6%) patients, respectively. In-hospital AKI occurred in 595 (11.8%) patients. The incidence of AKI was 10.5%, 9.5%, 11.8%, 10.0%, 12.8%, and 17.9% in patients with admission phosphate <2.4, 2.4-2.9, 2.9-3.4, 3.4-3.9, 3.9-4.4, and ≥4.4 mg/dL, respectively. After adjusting for potential confounders, admission serum phosphate levels >4.4 mg/dL was associated with an increased risk of developing AKI with an odds ratios of 1.72 (95% CI 1.20-2.47), whereas admission serum phosphate level <4.4 mg/dL was not associated with development of AKI during hospitalization.


Elevated admission phosphate was associated with an increased risk for in-hospital AKI.